Improvement in bit beaoes



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SAMUEL r.-

CE MIDDLETCWN, CONNECTICUT, AssIGNCE Tol HIM- SELE AND F. E. CLARK, or THESAME `ILACE.

Letters Patent No. 71,727, dated 'December 3, 18.67.

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TO ALL WHOM IT MAY CONCERN:

-Be it known that I, S. F. FENN,-of. 'Middletowm in the county of Middlesex, and State of Connecticut, have invented a new and useful Improvement in Bit-Brace; and I do hereby declare that the following is a full, clear, and exa-ct description thereof-y1 which will enable those skilled in theart to make and use the same, refciw `ence being had to the accompanying drawings, forming part yof this specification, in which Figurcl reprrcscuts a side view of my improved' bit-holder, attached to the ond-of abraoe. Figure 2 represents a view of the same on .another Sido. v f Figure 3 is a section taken in the linie a: xv, lig.' 1. I Figure4 is an end view.- Similar letters of reference indicate corresponding parts. This invention relates to an improvement in a bit-brace for holding 'the bit in its place in the end of the spindle after-a. hole has been bored, and when the bit is withdrawn therefrom. l VThe common method of securing the bit in the brace is by means of a set-screw, which catches in a notch -in the shank of a bi't. My improvement dispenses with the set-screw, and consstsin attaching a spring-stirrup by a pivot to thc round end of the spindle, which shall turn aside -to allow the bit to be introduced as usual intoA the brace, andA is then placed so as to catch over the round part of-the bit against theshouldcrs, formed by the square shank, and thus hold the bit in place, as hereiuaftermore particularly described;

A represents a round spindle of n. brace, or the ends ofnboring-stoek, which is provided with a square hole or deep recess in the point; for the reception of a boring-bit, as usual. Back of' the' base of the hole, in

the end of the brace, a stationary pin, b, is run through the centre, having ends projecting from the'sides. A.

stir-rup,a, is hung on Athe pivot b, formed of thin steel plates, the ends-of which are curved on the inner sides, to lit the outside of the spindle, in such manner that they shall lic close and bear against. the sides ofthe spindle by their spring pressure, when the stirrup` is placed in line therewith, for holding a bit in its place in the hole,

` and may'be turned on the pivotl, so as to spread without coming off, when the stirrup is turned, to put a bit in the brncc or take it therefrom. The lower end or'foot of the stirrup a i's'formed with a slot in it, which -.slips overrfhc round part of the bit, andcatches against the square shoulder thereof, to clamp and hold it inl the spindle, and preventvt from coming out, when the bit is withdrawn from a hole that has been bored, as shown'clcarly in the drawings. l l

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is. The spring-stirrup a, attached by the pivot b to the spindle A of a brace, constructed and operating substantially as and for the purpose described.

SAMUEL ETENN.

Witnesses:

B. W. TIIIIQCKMCIITON, CuAs. G. R. VINAL. 

